In Switzerland a sudden policy uncertainty shock happened in February 2014 with the close and largely unexpected acceptance of a referendum aiming at limiting free movement of persons. The referendum requires Switzerland to reintroduce annual quotas for immigrants within three years. The referendum is vaguely formulated and its actual consequences are largely unknown. Yet, the vote reduced the expected future availability of qualified labour, put at stake several economically important agreements between Switzerland and the European Union, and reduced expected future domestic demand for firms. This paper uses a special survey conducted by the KOF Swiss Economic Institute to analyse the short- to medium-run expected consequences of this substantial policy uncertainty shock on firms' private fixed investment and employment plans. We find that those firms that believe that potential growth in Switzerland will deteriorate and those that report that investment uncertainty has increased are also the ones that see a significant reduction in their future investment activities and their expected employment due to the vote, so that an uncertainty effect is present. We also provide evidence that the short-term effect of policy uncertainty on investment is economically significant.